12 Matching Results

Search Results

Advanced search parameters have been applied.

Data Evaluation for 56Co epsilon + beta+ Decay

Description: Recommended values for nuclear and atomic data pertaining to the {var_epsilon} + {beta}{sup +} decay of {sup 56}Co are provided here, followed by comments on evaluation procedures and a summary of all available experimental data. {sup 56}Co is a radionuclide which is potentially very useful for Ge detector efficiency calibration because it is readily produced via the {sup 56}Fe(p,n) reaction, its half-life of 77.24 days is conveniently long, and it provides a number of relatively strong {gamma} rays with energies up to {approx}3500 keV. The transition intensities recommended here for the strongest lines will be included in the forthcoming International Atomic Energy Agency Coordinated Research Programme document ''Update of X- and Gamma-ray Decay Data Standards for Detector Calibration and Other Applications'', and the analysis for all transitions along with relevant atomic data have been provided to the Decay Data Evaluation Project.
Date: February 28, 2005
Creator: Baglin, Coral M. & MacMahon, T. Desmond
Partner: UNT Libraries Government Documents Department

Isolation and Propterties of Curium

Description: The isolation of curium, element number 96, in relatively pure form has been accomplished. A method, involving a solvent extraction process, is given for the purification of americium from lanthanum and other ions. The discovery of a higher oxidation state of americium led to a method of separating americium from curium. Separation of the two elements was also accomplished by use of ion exchange resins. The details of the isolation of curium are given; the results of the spectrographic analysis, specific activity measurement, and calorimetric determination of half life showed the curium to be relatively pure. The absorption of light of various wave-lengths by an aqueous solution of Cm(III) is described, and some physical effects of the radiation from the curium are noted.
Date: July 28, 1948
Creator: Werner, L.B. & Perlman, I.
Partner: UNT Libraries Government Documents Department


Description: 3 8 ; 9 4 5 7 5 C 9 E ; < : 7over a 1456-day period. The half life was calculated to be 12.355 plus or minus 0.0l0 years, based on measurements in three calorimeters. The yields of /sup 208/Po and /sup 209/Po from the irradiation of multicurie quantities of /sup 210/Po were calculated. Production of small quantities of /sup 208/Po and /sup 209/Po is possible by the (n,xn) reaction; however, large quantities of /sup 210/Po would be present in the /sup 208/Po--/sup 209/Po sample. On the basis of these calculations the maximum /sup 208/Po content would occur after 466 days' irradiation in the materials testing reactor. An experimental decay scheme was drawn for /sup 208/Po on the basis of experimental data. Experiments are in progress to determine whether levels at about 1.4 Mev in /sup 208/Bi are populated in the electron capture decay of /sup 208/Po The known half-life method for determining the resolution time of a counting instrument was found to yield only an average value for the counting range in the computation. To correct the counting error a series of computations should be made with data covering only a short segment of the decay curve rather than a single computation covering the entire range. Alternatively, the decayingpair method of half life determination can be used, eliminating the need for an accurate knowledge of the resolution time. A process for the separation of /sup 234/U from /sup 238/Pu was developed. One batch of feed solution was processed by the method, and 14 mg of / sup 234/U were recovered. A second continuous solvent extraction process is being investigated. Thermogravimetric studies and the differential thermal analysis of potassium plutonium suifate dihydrate were completed. The previously reported DTA thermogram for salt was confirmed. The existence of the complex ...
Date: June 28, 1963
Creator: Eichelberger, J.F.; Grove, G.R. & Jones, L.V.
Partner: UNT Libraries Government Documents Department


Description: Performance assessments (PAs) are risk calculations used to estimate the amount of low-level radioactive waste that can be disposed at DOE sites. Distribution coefficients (K{sub d} values) are input parameters used in PA calculations to provide a measure of radionuclide sorption to sediment; the greater the K{sub d} value, the greater the sorption and the slower the estimated movement of the radionuclide through sediment. Understanding and quantifying K{sub d} value variability is important for estimating the uncertainty of PA calculations. Without this information, it is necessary to make overly conservative estimates about the possible limits of K{sub d} values, which in turn may increase disposal costs. Finally, technetium is commonly found to be amongst the radionuclides posing potential risk at waste disposal locations because it is believed to be highly mobile in its anionic form (pertechnetate, TcO{sub 4}{sup -}), it exists in relatively high concentrations in SRS waste, and it has a long half-life (213,000 years). The objectives of this laboratory study were to determine under SRS environmental conditions: (1) whether and to what extent TcO{sub 4}{sup -} sorbs to sediments, (2) the range of Tc K{sub d} values, (3) the distribution (normal or log-normal) of Tc K{sub d} values, and (4) how strongly Tc sorbs to SRS sediments through desorption experiments. Objective 3, to identify the Tc K{sub d} distribution is important because it provides a statistical description that influences stochastic modeling of estimated risk. The approach taken was to collect 26 sediments from a non-radioactive containing sediment core collected from E-Area, measure Tc K{sub d} values and then perform statistical analysis to describe the measured Tc K{sub d} values. The mean K{sub d} value was 3.4 {+-} 0.5 mL/g and ranged from -2.9 to 11.2 mL/g. The data did not have a Normal distribution (as defined by the ...
Date: October 28, 2008
Creator: Kaplan, D
Partner: UNT Libraries Government Documents Department

Measurement of the {sup 44}Ti half-life and its significance for supernova.

Description: In 1998, we reported the three-laboratory measurement of the {sup 44}Ti half-life which was determined relative to the well known value (5.2714 {+-} 0.0005 yr) of the {sup 60}Co half-life. We have continued the measurement at Argonne and Jerusalem and inclusion of data points for additional two years does not change our published value of 59.0 {+-} 0.6 yr.
Date: August 28, 1999
Creator: Ahmad, I.; Greene, J. P.; Kutschera, W. & Paul, M.
Partner: UNT Libraries Government Documents Department

Np Behavior in Synthesized Uranyl Phases: Results of Initial Tests

Description: Initial tests were completed at Pacific Northwest National Laboratory for developing a potential mechanism to retard the mobility of neptunium at the Yucca Mountain repository. Neptunium is of concern because of its mobility in the environment and long half life, contributing a large percentage of the potential dose over extended times at the perimeter of the site. The mobility of neptunium could be retarded by associating with uranium mineral phases. The following four uranium mineral phases were examined and are potential secondary phases expected to form as a result of interactions of spent nuclear fuel with the local environment: meta-schoepite, studtite, uranophane, and sodium boltwoodite. The fate of the neptunium was examined in these synthetic experiments.
Date: September 28, 2004
Creator: Friese, Judah I.; Douglas, Matthew; McNamara, Bruce K.; Clark, Sue B. & Hanson, Brady D.
Partner: UNT Libraries Government Documents Department

Recent searches for superheavy elements at the superhilac. [Cross section limits for Z = 110 to 118]

Description: The results of the search for superheavy elements are negative with respect to the finding of such elements. However, by assuming 2 spontaneous fission events as the lower limit of detection, the limits to their formation cross sections are calculated and plotted. It is noted that the half-life limits, also shown are easily within the huge uncertainties of the theoretical predicted half lives for any superheavy element nuclides produced in the experiment. 19 references. (JFP)
Date: March 28, 1978
Creator: Hulet, E.K.
Partner: UNT Libraries Government Documents Department